The present invention relates to a display unit in which a drive panel including a light-emitting device and a sealing panel face each other with a middle layer in between, and a method of manufacturing the display unit, and more specifically to a display unit suitable for an organic light-emitting display using a top emission organic light-emitting device, and a method of manufacturing the display unit.
In recent years, organic light-emitting displays using an organic light-emitting device as an alternative to liquid crystal displays have become a focus of attention. The organic light-emitting displays are of a self-luminous type, so it is considered that the organic light-emitting displays have advantages of a wide viewing angle, low power consumption and adequate response to high-definition high-speed video signals. Therefore, the organic light-emitting displays have been developed for practical use.
In the organic light-emitting display, for example, a drive device such as a TFT (thin film transistor) is formed on a substrate, and an organic light-emitting device is formed on the drive device with a planarization layer in between. The planarization layer is generally formed only in a display area (Japanese Patent Application Publication No. 2001-102168, fox example). On the other hand, there is such a structure that the planarization layer is extended beyond the display area to an area under a seal for adhering a protective casing to a peripheral portion of the back of the substrate, and the planarization layer is used as a buffer layer to absorb stress generated during curing of the seal (refer to Japanese Patent Application Publication No. 2001-102166, for example).
Moreover, as the material of the planarization layer, for example, a film capable of resisting a temperature for vaporizing moisture such as SOG (spin on glass) is proposed in order to prevent the entry of moisture into the organic light-emitting device (refer to Japanese Patent Application Publication No. 2001-102165, for example). Further, it is reported that a material including an epoxy-containing alkali-soluble resin and a 1,2 quinonediazido compound is used so that a through hole or the like can be formed with high resolution (refer to Japanese Patent Application Publication No. 2002-182380, for example).
In recent years, as an organic light-emitting display with high intensity and high aperture, a display with a top emission and all-solid-state sealing structure in which the whole surfaces of a drive panel and a sealing panel are bonded together with an adhesive layer in between, and light generated in the organic light-emitting device is extracted from the sealing panel has been proposed. Fox example, the drive panel includes a plurality of organic light-emitting devices on a drive substrate with a drive device layer such as a TFT and a coating layer as a planarization layer laid over the drive device layer in between.
However, in such a structure, the coating layer is formed all over a surface of the drive substrate without patterning the coating layer, so an end portion of the coating layer is exposed from an end portion of the adhesive layer. Therefore, external moisture may enter via the coating layer as a path, thereby resulting in degradation of the organic light-emitting devices.